In the tradition of the Shin Megami Tensei series, they are silent protagonists, with their personality based upon the player's actions and decisions, in Shin Megami Tensei: if....

In Persona, Tamaki Uchida frequently feuds with Tadashi Satomi. But during the Snow Queen Quest, when she was trapped in the Hypnos Tower along with Tadashi and others, they were imprisoned in a dream in which she and Tadashi are madly in love with each other. Their new feelings carry over into the real world after they were awoken from their slumber.

The protagonist's gender can be selected. They are a student of Karukozaka High School. They can choose to go with Yumi Shirakawa to rescue the school and its students, Reiko Akanezawa to find out the truth about Hazama and help save the school, Shinji Kuroi (also known as Charlie) to save themselves and escape while leaving the school behind or Akira Miyamoto to get revenge on Hazama.

In this sequel to the manga adaptation of if..., the male protagonist is called Nobu. Following the events of the manga, he has transferred to a new school, but has attracted attention from Thorman and Gotou for his connection to the incident in Karukozaka High School and the Demon Summoning Program he carries. He is framed for the death of his mother and forced to go on the run, reuniting once again with Yumi Shirakawa and the now-human Pixie. After Tokyo is flooded, he is taken to the future where he confronts the reincarnation of Hazama.

"A transfer student who joined the Fencing Club. She's always arguing with Tadashi."

—Her introduction, Persona

Localized as "Tammy" in Revelations, Tamaki seems to have transferred to St. Hermelin after the surreal events back in her old school (her fellow fencing club members will first be curious about why she never talks about her old school. When Mikage-cho becomes infested with demons, they will be even more mystified at her vast knowledge of demon behavior). She seems to have a bit of romantic tension with a clubmate named Tadashi Satomi, with whom she gets into a lot of intense shouting matches. Tamaki will also give the protagonist one of her fencing rapiers and some advice on how to deal with demons.

Tamaki is now in college and works part-time in the Kuzunoha Detective Agency as an assistant to Daisuke Todoroki, and also a Devil Summoner. She handles the mail-in magazine prizes for the party, and on one occasion, Tamaki will dress up as a cat burglar along with Tadashi (who is now her fiance) helping the party to rescue the schoolchildren trapped deep inside the burning Sky Museum.

On the Other Side, Tamaki still works at the Kuzunoha Detective Agency. She is also hiding a money-loving demon friend in the bathroom who uses the giant fortune cat in the office as a facade to ask random people for handouts. Tamaki reprises her role of handling the mail-in magazine contest entries for the party. Off-hand, she expresses concern for her fiance, who has been missing because of assassination threats from sources unknown.

Reiko's ending shows that Tamaki returns to level 1 after the school is back to normal, which would explain why in all of her cameos, she is not nearly as powerful as her status as a previous protagonist would suggest, retaining only the memories of the events of if... as experience about how to deal with demons.

Tamaki Uchida is modeled after Yuki Uchida, a popular actress and idol who the scenario writer of the Persona series at the time, Tadashi Satomi, liked. Satomi went so far to had his in-game cameo dating Tamaki which was not well-received by fans.

Tamaki being a member of the St. Hermelin fencing club is another reference to Yuki Uchida, as she is a fencer.

During the Aerospace Museum mission in Innocent Sin, Tamaki dresses like Hitomi Kisugi, the lead character of the manga Cat's Eye, and whom Yuki Uchida played as in the live action movie adaptation.

In if... Tamaki uses an Arm Terminal custom-made by Yawata, one of Karukozaka High School's teachers as her COMP. In Eternal Punishment however, she uses a GUMP from the Devil Summoner series when fighting against Tatsuya Sudou.